Surgical mask



April 25, 1967 CUNN|NGHAM ET AL 3,315,672

SURGI CAL MASK Filed July 10, 1964 INVENTORS fZ A/VA W CONA/l/VGHAM BY JAM/s5 K LUCK 4 rraQvE y:

United States Patent 3,315,672 SURGICAL MASK Frank W. Cunningham, 5007 Sharynne Lane, Torrance, Calif. 90505, and James V. Luck, 515 S. Rimpau Blvd., Los Angeles, Calif. 90005 Filed July 10, 1964, Ser. No. 381,622

2 Claims. (Cl. 128-139) The present invention relates to a surgical mask and more particularly to a surgical mask for excluding nasopharyngeal bacteria from an operative field.

Bacteriological studies of personnel, patients, and environment in surgical procedures have established that airborne infection of wounds during surgery has occurred by reason of the mere presence in the operating room of a disseminating carrier, conventionally masked, gowned, and shod. Cultures made of the clothing Worn by such a carrier during surgical procedures indicate bacteria accumulation in increasing numbers from the shoulders of the carrier down the front of his gown, in roughly the fall-out pattern of expired air during standing and sitting. Therefore, the agency of infection is apparently of nasopharyngeal origin, with bacteria being expelled through or about the disseminating carriers mask in the form of droplet nuclei which are airborne to aseptic areas such as the operative field.

Thus, despite control of airborne dust by air conditioning and filtering, use of ultraviolet light in the operating room to control bacteria, disinfection of the skin of the patient and of the operating room personnel, a major and serious source of contamination remains in the type of surgical mask presently being used. This type of mask is made of a porous material which covers the nose and mouth and acts as a filter for expired air during respiration and talking. As above adverted to, such masks have a demonstrated inability to prevent bacteriological expulsion therethrough during normal use in the operating room.

Accordingly, it is an object of the present invention to provide a surgical mask for excluding nasopharyngeal bacteria from the operative field by allowing inspired air to enter the mask through one-way air intake valves and by forcing expired air into a conduit for discharge at a point remote from the operative field.

Another object of the invention is the provision of a surgical mask of the aforementioned character which is relatively inexpensive, light in weight, and adapted to be worn without discomfort.

Another object of the invention is to provide such a surgical mask which is adapted to discharge expired air at a point immediately above the floor of the operating room, or which may be provided with means for attaching the mask apparatus to a standard suction line leading out of the operating room.

A further object of the invention is the provision of such a surgical mask which includes one or more air reflux passages between the intake valve means and the atmosphere outside of the mask, the passages being made of suflicient length to accommodate any backflow of air through the intake valve means on transition from inspiration to expiration. That is, valve closure is gen erally accompanied by escape of a limited amount of air from the mask through the intake valve means, and the reflux air passages accommodate this volume of escaped 3,315,672 Patented Apr. 25, 1967 air without permitting discharge thereof back into the operative field.

Another object of the invention is to provide a surgical mask of the aforementioned character which effects discharge of expired air through an elongated, flexible air exhaust conduit which terminates at a point immediately above the floor of the operating room and which is adapted to be secured to the wearers gown adjacent the shoulder for trailing behind the wearer out of his way during a surgical procedure.

Other objects and features of the invention will become apparent from consideration of the following description taken in connection with the accompanying drawings, in which:

FIG. 1 is a side elevational view .of a surgical mask according to the present invention, illustrated as the same would be worn by a user;

FIG. 2 is an enlarged side elevational view of the shield portion of the mask;

FIG. 3 is a rear elevational view of the shield portion of the mask;

FIG. 4 is an enlarged detail view taken along the line 4-4 of FIG. 3;

FIG. 5 is a side elevational view, .on a reduced scale, illustrating the mask in position upon a user and particularlyshowing the location of the discharge end of the exhaust conduit relative to the floor of the operating room;

FIG. 6 is a detail elevational view of the lower extremity of another form of exhaust conduit adapted for attachment to the suction line in a hospital operating room; and

FIG. 7 is a detail transverse view of an alternate form of intake valve. 7

Referring now to the drawings, there is illustrated a r surgical mask 10 according to the present invention and which comprises, generally, a shield 12 molded to the usual contours of the face and adapted to cover the nose and mouth of the user; one-way air intake means in the form of a pair of intake valves 14 attached to or forming an integral part of the shield 12; an elongated, flexible air exhaust conduit 16 coupled at its upper extremity to the shield 12 and terminating at its opposite extremity at a point immediately above the operating room floor, as best illustrated in FIG. 5; one-way air exhaust means constituted by an exhaust valve 18 attached to or forming an integral part of the shield 12; a fitting 22 mounted upon the exhaust conduit 16 and permitting the conduit 16 to be secured to the gown or other apparel of the user adjacent his shoulder; and an elastic band 24 attached to the shield 12 for securernent of the shield in position upon the face of the user.

The shield 12 may be made of any suitable air impermeable material such as resin-impregnated fiberglass or any of the so-called plastic materials such as acrylic material or the like. The shield preferably should closely conform to the facial contours of the user, but is spaced therefrom in the area adjacent the mouth and nose to provide a hollow portion or breathing chamber between the face and the interior surface of the shield for receiving expired air and the accompanying nasopharyngeal bacteria, as will be apparent.

The pair of intake valves 14 are located on opposite sides of the shields 12 and may be separate components attached thereto by suitable adhesives or plastic solvent, or may be molded as an integral part thereof. In the present instance the valves 14 are each constituted of a circular, apertured intake disk 26 which is integrally molded as a part of the shield 12. A valve element or intake flapper 28 of circular configuration is arranged upon the interior surface of each disk 26 in overlying, coextensive relationship and is secured in osition by a retaining plate 29 and a fastener such as the machine screw 30 illustrated in detail in FIG. 4.

Each flapper 28 is preferably a thin plastic film made of polyethylene or the like which is extremely flexible so that it is sensitively responsive to air flow through the apertures of the associated disk 26 or to slight differential pressures across the disk 26. Accordingly, the flappers 28 present minimum resistance to air flow and are characterized by minimal air reflux. With this arrangement, the flapper 28 is responsive on inspiration to uncover the apertures of the disk 26 and permit air flow into the breathing chamber of the shield 12, and responsive on expiration to cover the apertures and block such air flow. Thus, air flow is from the operative field and toward the user during inspiration.

On transition from inspiration to expiration there may occur a small amount of backflow of air through the intake disks 26 prior to complete blocking by the flappers 28 of communication between the breathing chamber and the atmosphere outside the shield 12. For this reason, a pair of elongated air reflux fairings 32, as best illustrated in FIG. 4, are integrally secured by adhesives or the like to the shield 12 and are located over the pair of disks 26, respectively, exteriorly of the outer surface of the shield 12. Each fairing 32 is closed at its lower extremity and open at its upper extremity to define an upwardly open reflux air passage 34 having an upper inlet opening to the atmosphere outside the shield and a lower outlet opening adjacent the inlet side of the associated intake disk 26. The length of the fairings 32 and consequently the length of the air passages 34 are made sufficient to accommodate any backflow of air through the apertured disks 26 on transition from inspiration to expiration. Thus, any small amount of air escaping outwardly through the intake disks 26 is entrapped in the air passages 34 and not permitted to escape into the operative field.

The exhaust conduit 16 is not only flexible but also extensible and retractible to a limited extent, being made, for example, by arranging a helical coil of wire or plastic material within an encompassing sleeve of flexible plastic material. Such conduits are well known in the art and are widely used on home vacuum cleaners, hair dryers, and the like.

For convenience and mobility of the surgeon or other user of the mask, the conduit 16 preferably includes a cylindrical fitting or sleeve 22 carrying a safety pin fastener 36 or the like to permit the conduit to be attached to the surgeons apparel adjacent the shoulder, the con duit 16 trailing behind the surgeon out of the way.

An air filter of fine pore size is attached to the lower extremity of the exhaust conduit 16 and minimizes bacterial discharge to the operating room, although the filter 20 can be eliminated and the lower extremity of the conduit connected instead to one of the usual standard operating room suction outlets (not shown), In this event, the conduit 16 would be made of suflicient length to reach the outlet, and the lower extremity of the conduit would be provided with attachment means, such as the locking lugs 38 illustrated in FIG. 6, to permit attachment to such outlet, as will be apparent.

Although the exhaust conduit 16 may be utilized as a reservoir for expired air, there is preferably employed the exhaust valve 18 which comprises a circular, apertured exhaust disk 40 molded as an integral part of the shield 12 adjacent the mouth area thereof. A circular exhaust flapper (not shown) identical to the intake flapper 28 is arranged in overlying and coextensive relationship to the disk 40 exteriorly thereof and is secured in the same manner as the flapper 28 is secured to the intake disk 26, that is, by means of a central fastener or machine screw 42. The exhaust flapper, like the intake flapper 28, is characterized by low resistance to air flow and minimal air reflux. Accordingly, the exhaust flapper is quickly responsive on expiration to cover the apertures in the exhaust disk 40 and permit air flow from the breathing chamber in the shield 12 into the upper end of the exhaust conduit 16, and responsive on inspiration to cover such apertures and prevent air flow from the exhaust coniluit 16 back into the breathing chamber.

Although the exhaust valve 18 may be oriented anywhere between the breathing chamber in the shield 12 and the discharge extremity of the exhaust conduit 16, it is preferably situated at the junction of the conduit 16 and the shield 12 for better response on transition from inspiration to expiration and vice versa.

Various types of intake and exhaust valves may be utilized in conjunction with the present mask 10, it being important primarily that the valve be a one-way valve which is sensitively responsive to air flow. For example, the intake valve structure could also take the form of an elongated sleeve 44 of thin plastic film, such as polyethylene or the like, located within the hollow interior of the mask 10. One extremity of the sleeve 44 is secured to the mask adjacent the inlet opening, and is open at its opposite extremity to the interior of the mask. Upon inhalation there is a free flow of air through the sleeve 44 to the interior of the mask but, upon exhalation, the thin material of the sleeve 44 collapses and outward flow from the sleeve 44 and through the inlet opening is thereby prevented. The length of the sleeve is made suflicient to provide a reflux chamber as abovedescribed in connection with the intake valves 14.

From the foregoing it will be apparent that the air impermeable surgical mask 10 of the present invention is capable of excluding nasopharyngeal bacteria from the operative field by confining exhaustion of expired air to a site remote from the operative field whereby the incidence of airborne wound infections by carriers who are nasopharyngeal shedders is substantially reduced.

Various modifications and changes may be made with regard to the foregoing detailed description without departing from the spirit of the invention or the scope of the following claims.

We claim:

1. A surgical mask for excluding nasopharyngeal bacteria from an operative field and comprising:

an air impermeable shield adapted to cover the nose and mouth and define a breathing chamber for receiving expired air;

one-way air intake means having an intake opening to said chamber to afford communication between said chamber and the atmosphere outside said shield on inspiration, and blocking said communication on expiration, said intake means further including means defining an elongated, vertically oriented reflux air passage having an outlet located adjacent said intake opening and an inlet located above said intake opening and adjacent the upper terminus of said shield, the length of said passage being suflicient to accommodate any backflow of air through said intake opening on transition from inspiration to expiration;

and an elongated, flexible air exhaust conduit coupled at one extremity to said shield for communication with said chamber and having suflicient length to terminate at its opposite extremity at a point remote from said operative field.

2. A surgical mask for excluding nasopharyngeal bacteria from an operative field according to claim 1 and including:

one-way air exhaust means oriented to afford communication between said chamber and said exhaust conduit on expiration and blocking said communication on inspiration.

References Cited by 119 Examiner UNITED STATES PATENTS 437,915 10/1890 Costigan 285401 1,101,898 6/1914 Barnhill 128139 1,221,446 4/1917 Hecht 128139 1,348,819 8/1920 Miller 128-141 6 2,858,828 11/1958 Matheson 128141 3,058,463 10/1962 Goodrich 128139 3,136,722 4/1964 Dempsey 128-143 FOREIGN PATENTS Ad. 28,334 11/1924 France.

RICHARD A. GAUDET, Primary Examiner.

K. HOWELL, Assistant Examiner. 

1. A SURGICAL MASK FOR EXCLUDING NASOPHARYNGEAL BACTERIA FROM AN OPERATIVE FIELD AND COMPRISING: AN AIR IMPERMEABLE SHIELD ADAPTED TO COVER THE NOSE AND MOUTH AND DEFINE A BREATHING CHAMBER FOR RECEIVING EXPIRED AIR; ONE-WAY AIR INTAKE MEANS HAVING AN INTAKE OPENING TO SAID CHAMBER TO AFFORD COMMUNICATION BETWEEN SAID CHAMBER AND THE ATMOSPHERE OUTSIDE SAID SHIELD ON INSPIRATION, AND BLOCKING SAID COMMUNICATION ON EXPIRATION, SAID INTAKE MEANS FURTHER INCLUDING MEANS DEFINING AN ELONGATED, VERTICALLY ORIENTED REFLUX AIR PASSAGE HAVING AN OUTLET LOCATED ADJACENT SAID INTAKE OPENING AND AN INLET LOCATED ABOVE SAID INTAKE OPENING AND ADJACENT THE UPPER TERMINUS OF SAID SHIELD, THE LENGTH OF SAID PASSAGE BEING SUFFICIENT TO ACCOMMODATE ANY BACKFLOW OF AIR THROUGH SAID INTAKE OPENING ON TRANSITION FROM INSPIRATION TO EXPIRATION; AND AN ELONGATED, FLEXIBLE AIR EXHAUST CONDUIT COUPLED AT ONE EXTREMITY TO SAID SHIELD FOR COMMUNICATION WITH SAID CHAMBER AND HAVING SUFFICIENT LENGTH TO TERMINATE AT ITS OPPOSITE EXTREMITY AT A POINT REMOTE FROM SAID OPERATIVE FIELD. 